Implement xas_object

Changes:

    * Implement xas_object as a base "class" for all playback state
      objects; allow implementation of start() and stop() methods to
      control playback

    * Move code for setting gain, bank slot to a new method,
      xas_bank_player_select()

    * Remove code from xas_bank_player_start() setting gain, bank slot

    * Add xas_object header to each monaural playable object

4 files changed, 35 insertions, 5 deletions

diff --git a/include/xas/bank.h b/include/xas/bank.h
index 33be492..cd1511e 100644
--- a/include/xas/bank.h
+++ b/include/xas/bank.h
@@ -3,6 +3,7 @@
 
 #include <sys/types.h>
 
+#include <xas/object.h>
 #include <xas/audio.h>
 
 enum xas_bank_player_status {
@@ -22,6 +23,8 @@ typedef struct _xas_bank {
 } xas_bank;
 
 typedef struct _xas_bank_player {
+    xas_object obj;
+
     xas_bank *bank;
     enum xas_bank_player_status status;
 
@@ -50,9 +53,11 @@ xas_bank_player *xas_bank_player_new(xas_bank *bank);
 
 void xas_bank_player_destroy(xas_bank_player *player);
 
-int xas_bank_player_start(xas_bank_player *player,
-                            size_t entry,
-                            float gain);
+int xas_bank_player_select(xas_bank_player *player,
+                             size_t entry,
+                             float gain);
+
+int xas_bank_player_start(xas_bank_player *player);
 
 int xas_bank_player_stop(xas_bank_player *player);
 
diff --git a/include/xas/object.h b/include/xas/object.h
new file mode 100644
index 0000000..b8b713b
--- /dev/null
+++ b/include/xas/object.h
@@ -0,0 +1,19 @@
+#ifndef _XAS_OBJECT_H
+#define _XAS_OBJECT_H
+
+typedef struct _xas_object xas_object;
+
+typedef int (*xas_object_start_callback)(xas_object *object);
+
+typedef int (*xas_object_stop_callback)(xas_object *object);
+
+struct _xas_object {
+    xas_object_start_callback start;
+    xas_object_stop_callback  stop;
+};
+
+int xas_object_start(xas_object *object);
+
+int xas_object_stop(xas_object *object);
+
+#endif /* _XAS_OBJECT_H */
diff --git a/include/xas/synth.h b/include/xas/synth.h
index 53f3343..61f50bc 100644
--- a/include/xas/synth.h
+++ b/include/xas/synth.h
@@ -4,6 +4,7 @@
 #include <stdint.h>
 #include <sys/types.h>
 
+#include <xas/object.h>
 #include <xas/audio.h>
 
 #define XAS_SYNTH_DEFAULT_FREQUENCY 2600 /* Hz */
@@ -25,6 +26,8 @@ typedef struct _xas_synth xas_synth;
 typedef int16_t (*xas_synth_sample_callback)(xas_synth *synth);
 
 struct _xas_synth {
+    xas_object obj;
+
     enum xas_synth_type  type;
     enum xas_synth_state state;
 
diff --git a/include/xas/vox.h b/include/xas/vox.h
index 5a1cacf..9d63bba 100644
--- a/include/xas/vox.h
+++ b/include/xas/vox.h
@@ -5,6 +5,7 @@
 #include <stdarg.h>
 #include <sys/types.h>
 
+#include <xas/object.h>
 #include <xas/audio.h>
 
 #define XAS_VOX_SETTINGS_TMP_PATH    "/tmp/xas-vox.XXXXXX"
@@ -16,6 +17,8 @@ enum xas_vox_state {
 };
 
 typedef struct _xas_vox {
+    xas_object obj;
+
     xas_audio_format format;
     size_t buffer_size;
 
@@ -66,12 +69,12 @@ int xas_vox_set_parameter_int(xas_vox *vox,
                                 const char *name,
                                 int value);
 
+int xas_vox_generate(xas_vox *vox);
+
 int xas_vox_stop(xas_vox *vox);
 
 int xas_vox_active(xas_vox *vox);
 
-int xas_vox_generate(xas_vox *vox);
-
 int xas_vox_vsayf(xas_vox *vox, const char *message, va_list args);
 
 int xas_vox_sayf(xas_vox *vox, const char *message, ...);